The present invention relates to a method and apparatus for the removal of real or false twist from a moving fabric in rope form.
Fabric that is subjected to finishing and/or dyeing processes in rope form such as in a jet dyer or the like is subject to receiving real or false twist during such processing. Thereafter, upon removal of the fabric from the processing equipment, it is necessary to open the fabric to its full width so that it can be properly fed to a tenter frame or the like for drying and/or heat setting of the fabric. Either false twist or real twist in the fabric while in rope form, will create problems during the opening of the fabric in preparation to feeding the fabric in open width to other processing equipment, particularly, where the fabric is in rope form and loosely stored in a container. A single end of the fabric is removed from the container for opening to its full width. During such opening operation, spreading forces will cause any real or false twist therein to move along the fabric rope in a direction opposite to the direction of opening. If too much twist is present in the fabric, the fabric will ultimately fail to open properly.
The present invention is designed to remove such real or false twist from fabric in rope form prior to spreading it, irrespective of the degrees of twist in the fabric, while at the same time enabling the process to continue unimpeded.
Various and sundry devices are known for use in removing twist from fabrics. One such device is described in commonly assigned U.S. Pat. No. 4,631,911 which is effective in removing twist from a moving fabric in rope form. It has now been found, that whenever fabric in rope form is transported and in a portion of its path moves vertically downwardly, any twist in the fabric drops quickly to the bottom of the vertical path. Further, if such fabric forms a U-shaped loop at the lower end of the vertical leg, the twist tends to accumulate around the nadir of the U-shaped loop. Apparently the force of gravity tends to cause any such remaining twist in the fabric to gravitate towards the nadir of the loop.
It has now been found that an optimum and preferred position for measuring twist remaining in a fabric following a path as defined above in which a U-shaped loop is present in the path is at a point between the nadir of the fabric loop and a downstream fabric spreading mechanism.
No prior art is known that teach or suggest the apparatus or method of the present invention.